Color cathode ray tube

Abstract

A color cathode ray tube (CRT) has a panel having a fluorescent film consisting of a number of groups of phosphors each radiating in a particular color. A shadow mask adjoins the fluorescent film and is formed with a number of apertures by etching. Electron guns are located at the side opposite to the fluorescent film with respect to the shadow mask, and emit electron beams for causing the phosphors to radiate. An insulating glass layer covers the edges of the apertures on the side of the shadow mask that faces the fluorescent film. The glass layer increases the mechanical strength of the shadow mask and enhances landing accuracy.

What is claimed is: 
     
       1. A color cathode ray tube (CRT) comprising: a panel having a fluorescent film comprising a number of groups of phosphors each radiating in a particular color;   a shadow mask positioned in spaced relationship to said fluorescent film and formed with a number of apertures by etching;   electron beam focusing means disposed on a side of said shadow mask facing said fluorescent film, said focusing means comprising: an insulating glass layer covering edges of said apertures exclusively on a side of said shadow mask that faces said fluorescent film;   and a conductive layer formed on said insulating glass layer and electrically insulated from said shadow mask,   whereby charge is deposited on said insulating glass layer in a uniform distribution; and     electron guns located at a side of said shadow mask opposite from said fluorescent film and said insulating glass layer, and for emitting electron beams for causing said number of groups of phosphors to radiate.   
     
     
       2. A color CRT as claimed in claim 1, wherein said glass layer comprises glass having a coefficient of thermal expansion that is smaller than a coefficient of expansion of said shadow mask, whereby a compression stress acts on said glass layer.